

I absolutely despise Firebase Firestore (the database technology that was “hacked”). It’s like a clarion call for amateur developers, especially low rate/skill contractors who clearly picked it not as part of a considered tech stack, but merely as the simplest and most lax hammer out there. Clearly even DynamoDB with an API gateway is too scary for some professionals. It almost always interfaces directly with clients/the internet without sufficient security rules preventing access to private information (or entire database deletion), and no real forethought as to ongoing maintenance and technical debt.
A Firestore database facing the client directly on any serious project is a code smell in my opinion.
I agree that this is ultimately a problem with developers lacking security knowledge and general understanding, but my issue with Firestore specifically is that it is a powerful tool that, while it can be adopted as part of a carefully considered tech stack, lends itself most naturally towards being a blunt force instrument used by these kinds of developers.
My main criticism of Firestore is that it offers a powerful feature set that is both extremely attractive to amateur or constrained developers while simultaneously doing a poor job of guiding said amateurs towards creating a secure and well designed backend. In particular, the seemingly expected use case of the technology as something directly interfaced with by apps and other clients, as evidenced by the substantial support and feature set for this use case, is the main issue. This no-code no-management client driven interaction model makes it especially attractive to these developers.
This lack of indirection through an API Gateway or service, however, imposes additional design considerations largely delegated to the security rules which can easily be missed by a beginner. For example:
All of these pitfalls can be worked around (although I would still argue for some layer of indirection at least for writes), but at this point I’ve been contracted to 2 or 3 projects worked on by “professionals” (derogatory) that failed to account for any of these issues and I absolutely sick to death of it. I think a measure of a tools quality is whether it guides a developer towards good practices by design and I have found Firestore to completely fail in that regard. I think it can be used well, and it is perfectly appropriate for small inconsequential (as in data leaks would be inconsequential) single developer projects, but it almost never is.